Color reversal development process utilizing a preliminary development bath free of bromide ions



United States Patent 4 Claims. ion. 96-22) This invention relates to an improved reversal development process according to which an exposed multicolor photographic reversal film is subjected to a preliminary treatment in a developing bath that is free from bromides before being finally developed in a bromidecontaining developing bath.

It is known that positive multi-color photographic images can be produced directly. With these processes, the latent image produced in the light-sensitive silver halide layer by the exposure to light is usually blackened in a black-and-White developer. Thereafter the photographic film is rinsed, exposed to dittused light and the residual silver halide developed to a multi-color positive image with known color-forming developers in particular of the primary aromatic amine type. In this process it is difiicult to obtain the desired gradation which usually turns out to be too steep and can only be slightly influenced by changes in the preparation of the emulsion. This too steep gradation, which is connected with reversal development, was one of the main reasons why satisfactory positive color prints could not be directly produced from transparencies.

Another obstacle in the way of producing a direct positive multi-color print on a paper support by the reversal development process is the so-called grittiness. By this term is to be understood non-uniform development which produces the impression of a greatly exag gerated coarseness of grain. This grittiness is caused largely in the biack-and-white development. The alkalinity, the nature and concentration of silver halide solvents and the development time are responsible for these effects.

It is among the present objects of the invention to overcome these ditficulties and to provide a method for the production of multi-color transparencies which are suitable for the preparation of multi-color positive prints. The objects can be attained by treating the exposed multicolor reversal film firstly in a preliminary bath free from bromide ions and developing finally in a developer containing bromide. The preliminary bath advantageously only contains the developer compound and has a pH-value lower than 7. p

The advantages of this development process are:

(1) Shortening of the development time. The sum of the times in the bromide-free preliminary bath and bromide-containing developer can be kept considerably shorter than with conventional development. This is a great advantage, in particular for mechanical processing, which is almost exclusively involved with reversal materials, since a shortening of the development time at a given speed of travel permits the use of fewer developer tanks.

(2) Reduction of the grittiness. -The grittiness observed with direct positive multi-color prints on a paper support that was referred to hereinbefore disappears when processing is carried out according to the process of the presentinvention. I

(3) Levelling of the gradation. When processing according to the process of the present invention, gamrnavalues are obtained which are 0.3 to 0.5 unit lower than with conventional processing.

(4) Improvement in the'color reproduction. This can be explained by the fact that with the preliminary development of an exposed layer of a multilayer material in the preliminary bath, the reaction products that are formed diffuse into the adjacent unexposed layers and reduce the fogging therein, while at the areas where none of the three layers is exposed, a small degree of fogging is formed in all three layers. (5) A very high degree of uniformity and productiveness of the developing baths, especially when the bromidefree preliminary bath has the same or a somewhat higher concentration of the same developer as the bromidecontaining developer bath.

Example A multi-color material which is intended for the production of direct positive multi-color images from color transparencies is prepared as follows:

Onto a baryta coated paper support is cast a silver halide gelatin emulsion layer containing the yellow coupler Ta 521 which is Z-(methyloctalecylamino)-4-carboxyalpha-anisoylacetanilide. The silver halide consists of 98.5% of silver bromide and 1.5% of silver iodide. The layer contains 0.7 g. of silver per m.

This layer is overcoated with a second silver halide gelatin emulsion layer containing the sodium salt of the magenta coupler Z 169. which is l-(3-sulfo-4-phenoxyphenyl)-3-heptadecyl-S-pyrazolone that is sensitized for the green range of the visible spectrum with the sensitizing dyestufi Rr 340 which is the thiocyanate of 3,3-diethyl-9- ethyl-5,5-diphenyloxacarbocyanine.

The silver halide of this layer consists of 90% of silver chloride and 10% of silverbromide. The silver content of both layers is equivalent to 1.0 g. per m.

Onto the green sensitized emulsion layer is coated a silver halide emulsion layer consisting of the same silver halide emulsion but being sensitized for the red range of the visible spectrum with the sensitizing dyestutf MA 1088 which is the iodide of 3'-ethyl-tetrahydro-alpha-naphthm thiazole meso phenylethyl rhodanine L 3 ethyl 4,5- diphenylthiazole complex dimethine merocyanine. This layer contains the cyan coupler F 654 which is the sodium salt of N [2 (N -methyl-N-heptadecylamino)-4-sulfophenyl]-l-hydroxy-2-naphthamide. The multilayer material contains 1.3 g. of silver per m.

Three samples of the multi-color material described above are exposed through a test wedge. The blackand-white development of each of these samples is precformed as described hereinafter in a different manner while the further processing of the samples is identical.

Sample (a) is developed to black-and-white in a developer having the following composition:

2 g. of Calgon (a sodium hex-ametaphospha-te-containing detergent) 10 g. of sodium sulphite 4g. of hydroquinone 8 g. of KBr 40 g. of K CO 0.050 g. of 1-phenyl-3-pyrazolid0ne 1000 ml. of water The development time is 5 minutes at 20 C.

- The further processing takes place in the usual manner by rinsing for 10 minutes, exposing [for 30 seconds to diffused day-light and subsequent development in a colortorming developer having the following composition:

3 g. of diethyl-p-phenylene diamine sulphate g, of potassium carbonate 2 g. of hydroxylaminehydrochloride 2 g. of potassium bromide 2 g. of Calgon (a sodium hexametaphosphate-containing detergent) 1.5 g. of sodium sulphite 1000 ml. of water The development time is 8 minutes at 20 C.

After the color-forming development the material is treated in a stop bath, rinsed, bleach-fixed, rinsed again and dried.

The resulting wedge shows satisfactory whites and deep blacks, but has a gamma-value of 1.7. Such a gammavalue is however too steep for the reproduction of transparency images.

Sample (b) was developed in a developer of the following composition and thereafter processed in the usual manner as described in connection with sample (a) hereinbefore:

2 g. of Calgon (a sodium hexametaphosphate-containing detergent) 4 g. of sodium sulphit 6 g. of KBr 4 g. of 1-phenyl-3-pyrazolidone 20 of K2CO3 1000 g. of water Even with a development time of 10 minutes, still no whites are obtained, although the blacks are already unsatisfactory on account of the fogging of the uppermost cast layer. The image is moreover very gritty.

-(c) The third sample is firstly treated for 1 minute at C. in a preliminary bath of the following compo sition:

4.5 g. of potassium meta-bisulphite 4 g. of 1-phenyl-3-pyrazolidone 0.75 g. of NaHSO 5 cc. of Agepon (a sodium paraffin sulfonate) 1000 ml. of water Thereafter it is immediately developed for 4 minutes at 20 C. in the developer composition referred to under (b) and further processed in the usual manner as described under (a). The resulting wedge shows very good whites and deep blacks and has a gamma-value of 1.3 which is quite suitable for the reproduction of color transparencies. No grittiness is observed.

While there have been pointed out above certain preferred embodiments of the invention, the same is not limited to the foregoing examples or to the specific de tails given therein, but are capable of numerous variations and embodiments as to the materials, products, proportions and conditions employed.

For example the photographic materials used may comprise transparent or matt supports, e.'g., sheets of cellulose esters, polycar-bonates, particularly those produced from bis-phenylolalkanes, polyesters, e.g., polyethylene terephthalate, or paper. The layer arrangement of the multi color material is not especially critical and may be selected according to the special requirements of the reproduction process in which the material is to be used.

The developing process according to the invention can be used for developing separate color photographic layers as well as black-and-white positives.

The preliminary bath and the developing bath preferably contain the same developing compound. Preferred developers are 1-phenyl-3-pyrazolidone and derivatives thereof, alone or in combination with glycine. In principle however, other developers or developer combinations can also be employed, for example, hydroquinone, p-aminophenol and derivatives thereof, diaminophenol, developers of the 4-amino-pyrazolone(5) or the 3-amino- A -pyrazoline series and the like. The developing concentration is 1-10 g. per liter of the aqueous preliminary bath. I

The preliminary bath can contain other conventional additives, such as anti-fogging agents, stabilizers, additines for adjusting the pH-value, which has to be about 7 or below, for example, alkali-metal bisulfa-tes or wetting agents. Suitable stabilizers or preserving agents are, for example, alkali-metal suifites, bisulfites or mctabisulfites, and ascorbic acid.

The black-and-white developer may also contain conventional additives such as alkalizing agents, e.g., alkalimetal carbonates, borates, phosphates or hydroxides, preserving agents as described above, stabilizing agents, potassium bromide, etc.

We claim:

1. In a reversal process for the production of a multicolor photographic image which comprises 7 (a) exposing a light-sensitive multicolor photographic material to an object to be reproduced,

(b) developing the exposed material in an aqueous alkaline developer composition containing a blackand-white developer and bromide ion to produce a silver image therein,

(0) uniformly exposing the thus developed photographic material to diffused actinic light,

(d) developing the uniformly exposed photographic material in a color-forming developer composition containing a primary aromatic amine developer to produce a colored image therein, and

(e) bleaching and fixing the color-developed photographic material,

the improvement which comprises subjecting the image- Wise exposed photographic material (a) prior to development (b) to preliminary treatment in an aqueous developer composition that is free from bromide ions, has a pH below about 7.0, and contains between 1 and 10 grams per liter of a developer of the group consisting of blackand-white developers of the 1-phenyl-3-pyrazolidone, hydroquinone, p-aminophenol, diaminophenol, 4-amino-5- pyrazoline and 3-amino-A -pyrazoline types.

2. A process as defined in claim 1 in which the aqueous developer composition that is free from bromide ions contains a preserving agent of the class consisting of alkali-metal sulphites, alkali-metal bisulphites and alkalimetal metabisulfites.

3. A process as defined in claim 1 in which the blackand-white developer is 1-phenyl-3-pyrazolidone.

4. A process as defined in claim 1 in which the blackand-white developer is a mixture of 1-phenyl-3-pyrazolidone with glycine.

References Cited by the Examiner UNITED STATES PATENTS 1,525,766 2/25 Capstaif 96-59 1,973,466 9/34 Crabtree 96-66 2,196,036 3/40 Searcy 96-22 2,324,123 7/43 Weissberger 96-66 2,456,956 12/48 Knott et a1. 96-22 2,622,025 12/52 Waller et a1. 96-59 2,712,995 7/55 Weyde 96-22 OTHER REFERENCES Scharnke: Chemical Abstracts, vol. 54, page 22117 (1960).

Varden: Chemical Abstracts, vol. 35, page 3181 (1941). (Copies of above in Scientific Library.)

Crabtree et al.: Journal Society Motion Pictures Engineering, vol. 21, pp. 21-53 (1933). (Copy in Scientific Library.)

Baines: The Science of Photography, pages -6, John Wiley & Sons, New York (1958). (Copy in Scientific Library.)

NORMAN G. TORCHIN, Primary Examiner. 

1. IN A REVERSAL PROCESS FOR THE PRODUCTION OF A MULTICOLOR PHOTOGRAPHIC IMAGE WHICH COMPRISES (A) EXPOSING A LIGHT-SENSITIVE MULTICOLOR PHOTOGRAPHIC MATERIAL TO AN OBJECT TO BE REPRODUCED, (B) DEVELOPING THE EXPOSED MATERIAL IN AN AQUEOUS ALKALINE DEVELOPER COMPOSITION CONTAINING A BLACKAND-WHITE DEVELOPER AND BROMIDE ION TO PRODUCE A SILVER IMAGE THEREIN, (C) UNIFORMLY EXPOSING THE THUS DEVELOPED PHTOGRAPHIC MATERIAL TO DIFFUSED ACTINIC LIGHT, (D) DEVELOPING THE UNIFORMLY EXPOSED PHOTOGRAPHIC MATERIAL IN A COLOR-FORMING DEVELOPER COMPOSITION CONTAINING A PRIMARY AROMATIC AMINE DEVELOPER TO PRODUCE A COLORED IMAGE THEREIN, AND (E) BLEACHING AND FIXING THE COLOR-DEVELOPED PHOTOGRAPHIC MATERIAL, THE IMPROVEMENT WHICH COMPRISES SUBJECTING THE IMAGEWISE EXPOSED PHOTOGRAPHIC MATERIAL (A) PRIOR TO DEVELOPMENT (B) TO PRELIMINARY TREATMENT IN AN AQUEOUS DEVELOPER COMPOSITION THAT IS FREE FROM BROMIDE IONS, HAS A PH BELOW ABOUT 7.0, AND CONTAINS BETWEEN 1 AND 10 GRAMS PER LITER OF A DEVELOPER OF THE GROUP CONSISTING OF BLACKAND-WHITE DEVELOPERS OF THE 1-PHENYL-3-PYRAZOLIDONE, HYDROQUINONE, P-AMINOPHENOL, DIAMINOPHENOL, 4-AMINO-5PYRAZOLINE AND 3-AMINO-$2-PYRAZOLNE TYPES. 